@Article{ xp,
	title = "{Una explicación de la programación extrema. Aceptar el cambio}",
	author = "Beck, K.. “Extreme Programming Explained. Embrace Change",
	pages = "1485--1490",
	year = "2000",
},


@Unpublished{ web,
	url = "http://www.denso-wave.com/qrcode/aboutqr-e.html",
	title = "http://www.denso-wave.com/qrcode/aboutqr-e.html"
}

